Browse Prior Art Database

Message Compression Method

IP.com Disclosure Number: IPCOM000051604D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 41K

Publishing Venue

IBM

Related People

Berg, EJ: AUTHOR [+4]

Abstract

A table of often used words, sentences, and phrases is maintained in a interactive terminal memory. Selected ones of the stored words, sentences, and phrases are identified by command and address bytes for insertion into a message being received over a communication line to avoid the need for sending the entire word, sentence, or phrase over a communication line.

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Message Compression Method

A table of often used words, sentences, and phrases is maintained in a interactive terminal memory. Selected ones of the stored words, sentences, and phrases are identified by command and address bytes for insertion into a message being received over a communication line to avoid the need for sending the entire word, sentence, or phrase over a communication line.

In interactive communication networks such as point of sale or finance applications, it is often necessary to print or display a form header, a guidance message or a relatively common surname as part of a transaction. The figure shows an example of the name Morrison being retrieved from a local memory for insertion into a message to be printed on the bill of sale. In order to permit up to 256 different messages to be stored and accessed using a single byte address, an indirect address buffer 11 is provided having 256 sixteen-bit entries. Each sixteen-bit indirect address buffer entry is the real address in a data buffer which can be up to 64K long.

As the compressed message of the figure is received at the terminal, each character, including the characters J. L., is placed in the print buffer until the command AM1 is received. The command, after being decoded, causes the following binary number 25 address not to be stored in the print buffer, but instead access address 25 of the indirect address buffer 11. Contained in the address 25 location is the binary number address 1025, which is the address of the start of the word Morrison in data buffer 13. The first byte at address 1025 of data buffer 13 is a link count indicating how many characters are to be transferred from data buffer 13 to the print buffer. After the eight characters have been transferred to the print buffer, the print buffer continues to accept communicated data characters directly from the communication line until a new command is received.

Although the command AM1 of the figure is an eight-bit...